Which refers back to original question. WHY DOESNT GM OFFER THIS?
SLP runs approximately $10000 over MSRP for this for a base package with includes wheels and such. GM CAN offer this in an SS as an option for around $8000 over MSRP and make a profit. If SLP does it for this cost, and they dont do this for free, GM can do this as well.

What the ZL700 is 35K over the car cost then start adding wheels to it and your over 70K for the car.